(a) Technical Field
The present disclosure relates to a display device. More particularly, the present disclosure relates to a vertical alignment (VA) mode liquid crystal display.
(b) Description of the Related Art
A display device, such as a liquid crystal display (LCD) and an organic light diode display, generally includes a display panel including a plurality of pixels as a unit displaying an image.
The display panel of a liquid crystal display generally includes a liquid crystal layer of liquid crystal molecules, a field generating electrode configured to control the alignment of the liquid crystal molecules of the liquid crystal layer, a plurality of signal lines configured to apply a voltage to at least a portion of the field generating electrode, and a plurality of switching element connected thereto. When a voltage is applied to the field generating electrode, an electric field is generated in the liquid crystal layer such that the liquid crystal molecules are rearranged, thereby controlling the amount of light transmitted by the liquid crystal layer to display an image. To control the amount of the transmitted light, the display panel may include at least one polarizer.
The field generating electrode included in the liquid crystal display includes a pixel electrode applied with a data voltage and an opposed electrode applied with a common voltage. The pixel electrode may be applied with the data voltage through a switching element, which may be a thin film transistor. The pixel electrode and the opposed electrode may be positioned on opposite sides of the liquid crystal layer, or may be positioned on the same side with respect to the liquid crystal layer.
The liquid crystal display may have a vertical alignment (VA) mode in which long axes of the liquid crystal molecules are aligned almost vertical to the surface of the display panel in the absence of an electric field to the liquid crystal layer. The liquid crystal display of the vertical alignment (VA) mode may easily realize a large contrast ratio and a wide reference viewing angle compared with other modes.
In the vertical alignment (VA) mode liquid crystal display, to realize the wide viewing angle, a plurality of sub-regions or domains having different alignment directions of the liquid crystal molecules may be formed in one pixel. As one example of forming the plurality of domains in one pixel, there is a method of forming cutouts of minute slits in the field generating electrodes. If the cutouts are formed in the field generating electrode, a fringe field is generated at an edge of the cutout, thereby rearranging the liquid crystal molecules to form the plurality of domains by.
The liquid crystal display has a structure in which a plurality of layers are deposited, and an exposure process using a photomask is used to form a pattern of each layer.
To define an initial alignment of the liquid crystal molecules of the liquid crystal display, an alignment layer is positioned on an inner surface opposing the liquid crystal layer among surfaces of the display panel. For example, the alignment layer may be formed by coating the alignment layer on the inner surface of the display panel. However, control of the alignment layer at the edge thereof is not easy because the aligning agent may spread in a plan view. If the edge of the region where the alignment layer is formed is not controlled, a sealant adhering two panels including the display panel may contact the alignment layer, or a region where the alignment layer is not coated may be generated on the display area displaying the image. If the alignment layer contacts the sealant, adherence of the sealant is weak, absorption is generated such that reliability is decreased, and resistance of an electrical short point may be increased between two panels. When the alignment layer is not coated on the edge portion of the display area, the initial alignment of the liquid crystal molecules is not defined such that a display defect is generated. These problems may be prevented if a margin of the region where the alignment layer is formed is increased such that a distance between the display area and the sealant is far and a non-display area of the edge of the display device may be widened.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.